1. Field of the Invention
The present invention relates to a medical pump device.
2. Description of Related Art
In the field of medicine, medical pump devices are used for introducing an exactly dosed rate of an infusion liquid into the body of a patient. Because of the high sterility requirements, medical pump devices uses hose pumps in which the liquid is advanced by repeatedly squeezing a pump hose. The pump hose is a one-way hose that is thrown away after use. Therefore, its production costs should be as low as possible. The same is true for other pump devices, e.g. blood pumps that draw blood from a patient's body or supply blood thereto. Also in this case, it is most important to obtain and maintain a desired rate of delivery.
The rate of delivery of a hose pump depends largely on the accuracy of the size of the pump hose. Prior to the present invention, particular importance was attributed to the production of a pump hose having a high degree of accuracy with respect to size, so as to exactly obtain a desired delivery rate. If the delivery volume of such pump hose lay beyond certain tolerance limits, the pump hoses were sorted out as waste. However, within the tolerance limits, the pump hoses used still have considerable deviations in the delivery volume. If narrow tolerances are chosen, a lot of waste is produced. If wide tolerances are chosen, large deviations of the delivery rate from the set delivery rate will occur.
It is an object of the present invention to provide a medical pump device in which an exact observation of the desired delivery rate is obtained without any particular requirements as to the accuracy of the size of the pump hose.